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<a name="Developer-Options"></a>
<div class="header">
<p>
Next: <a href="Submodel-Options.html#Submodel-Options" accesskey="n" rel="next">Submodel Options</a>, Previous: <a href="Code-Gen-Options.html#Code-Gen-Options" accesskey="p" rel="prev">Code Gen Options</a>, Up: <a href="Invoking-GCC.html#Invoking-GCC" accesskey="u" rel="up">Invoking GCC</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="GCC-Developer-Options"></a>
<h3 class="section">3.18 GCC Developer Options</h3>
<a name="index-developer-options"></a>
<a name="index-debugging-GCC"></a>
<a name="index-debug-dump-options"></a>
<a name="index-dump-options"></a>
<a name="index-compilation-statistics"></a>

<p>This section describes command-line options that are primarily of
interest to GCC developers, including options to support compiler
testing and investigation of compiler bugs and compile-time
performance problems.  This includes options that produce debug dumps
at various points in the compilation; that print statistics such as
memory use and execution time; and that print information about GCC&rsquo;s
configuration, such as where it searches for libraries.  You should
rarely need to use any of these options for ordinary compilation and
linking tasks.
</p>
<p>Many developer options that cause GCC to dump output to a file take an
optional &lsquo;<samp>=<var>filename</var></samp>&rsquo; suffix. You can specify &lsquo;<samp>stdout</samp>&rsquo;
or &lsquo;<samp>-</samp>&rsquo; to dump to standard output, and &lsquo;<samp>stderr</samp>&rsquo; for standard
error.
</p>
<p>If &lsquo;<samp>=<var>filename</var></samp>&rsquo; is omitted, a default dump file name is
constructed by concatenating the base dump file name, a pass number,
phase letter, and pass name.  The base dump file name is the name of
output file produced by the compiler if explicitly specified and not
an executable; otherwise it is the source file name.
The pass number is determined by the order passes are registered with
the compiler&rsquo;s pass manager. 
This is generally the same as the order of execution, but passes
registered by plugins, target-specific passes, or passes that are
otherwise registered late are numbered higher than the pass named
&lsquo;<samp>final</samp>&rsquo;, even if they are executed earlier.  The phase letter is
one of &lsquo;<samp>i</samp>&rsquo; (inter-procedural analysis), &lsquo;<samp>l</samp>&rsquo;
(language-specific), &lsquo;<samp>r</samp>&rsquo; (RTL), or &lsquo;<samp>t</samp>&rsquo; (tree). 
The files are created in the directory of the output file. 
</p>
<dl compact="compact">
<dd>
<a name="index-fcallgraph_002dinfo"></a>
</dd>
<dt><code>-fcallgraph-info</code></dt>
<dt><code>-fcallgraph-info=<var>MARKERS</var></code></dt>
<dd><p>Makes the compiler output callgraph information for the program, on a
per-object-file basis.  The information is generated in the common VCG
format.  It can be decorated with additional, per-node and/or per-edge
information, if a list of comma-separated markers is additionally
specified.  When the <code>su</code> marker is specified, the callgraph is
decorated with stack usage information; it is equivalent to
<samp>-fstack-usage</samp>.  When the <code>da</code> marker is specified, the
callgraph is decorated with information about dynamically allocated
objects.
</p>
<p>When compiling with <samp>-flto</samp>, no callgraph information is output
along with the object file.  At LTO link time, <samp>-fcallgraph-info</samp>
may generate multiple callgraph information files next to intermediate
LTO output files.
</p>
<a name="index-d-1"></a>
<a name="index-fdump_002drtl_002dpass"></a>
</dd>
<dt><code>-d<var>letters</var></code></dt>
<dt><code>-fdump-rtl-<var>pass</var></code></dt>
<dt><code>-fdump-rtl-<var>pass</var>=<var>filename</var></code></dt>
<dd><p>Says to make debugging dumps during compilation at times specified by
<var>letters</var>.  This is used for debugging the RTL-based passes of the
compiler.
</p>
<p>Some <samp>-d<var>letters</var></samp> switches have different meaning when
<samp>-E</samp> is used for preprocessing.  See <a href="Preprocessor-Options.html#Preprocessor-Options">Preprocessor Options</a>,
for information about preprocessor-specific dump options.
</p>
<p>Debug dumps can be enabled with a <samp>-fdump-rtl</samp> switch or some
<samp>-d</samp> option <var>letters</var>.  Here are the possible
letters for use in <var>pass</var> and <var>letters</var>, and their meanings:
</p>
<dl compact="compact">
<dd>
<a name="index-fdump_002drtl_002dalignments"></a>
</dd>
<dt><code>-fdump-rtl-alignments</code></dt>
<dd><p>Dump after branch alignments have been computed.
</p>
<a name="index-fdump_002drtl_002dasmcons"></a>
</dd>
<dt><code>-fdump-rtl-asmcons</code></dt>
<dd><p>Dump after fixing rtl statements that have unsatisfied in/out constraints.
</p>
<a name="index-fdump_002drtl_002dauto_005finc_005fdec"></a>
</dd>
<dt><code>-fdump-rtl-auto_inc_dec</code></dt>
<dd><p>Dump after auto-inc-dec discovery.  This pass is only run on
architectures that have auto inc or auto dec instructions.
</p>
<a name="index-fdump_002drtl_002dbarriers"></a>
</dd>
<dt><code>-fdump-rtl-barriers</code></dt>
<dd><p>Dump after cleaning up the barrier instructions.
</p>
<a name="index-fdump_002drtl_002dbbpart"></a>
</dd>
<dt><code>-fdump-rtl-bbpart</code></dt>
<dd><p>Dump after partitioning hot and cold basic blocks.
</p>
<a name="index-fdump_002drtl_002dbbro"></a>
</dd>
<dt><code>-fdump-rtl-bbro</code></dt>
<dd><p>Dump after block reordering.
</p>
<a name="index-fdump_002drtl_002dbtl2"></a>
<a name="index-fdump_002drtl_002dbtl2-1"></a>
</dd>
<dt><code>-fdump-rtl-btl1</code></dt>
<dt><code>-fdump-rtl-btl2</code></dt>
<dd><p><samp>-fdump-rtl-btl1</samp> and <samp>-fdump-rtl-btl2</samp> enable dumping
after the two branch
target load optimization passes.
</p>
<a name="index-fdump_002drtl_002dbypass"></a>
</dd>
<dt><code>-fdump-rtl-bypass</code></dt>
<dd><p>Dump after jump bypassing and control flow optimizations.
</p>
<a name="index-fdump_002drtl_002dcombine"></a>
</dd>
<dt><code>-fdump-rtl-combine</code></dt>
<dd><p>Dump after the RTL instruction combination pass.
</p>
<a name="index-fdump_002drtl_002dcompgotos"></a>
</dd>
<dt><code>-fdump-rtl-compgotos</code></dt>
<dd><p>Dump after duplicating the computed gotos.
</p>
<a name="index-fdump_002drtl_002dce1"></a>
<a name="index-fdump_002drtl_002dce2"></a>
<a name="index-fdump_002drtl_002dce3"></a>
</dd>
<dt><code>-fdump-rtl-ce1</code></dt>
<dt><code>-fdump-rtl-ce2</code></dt>
<dt><code>-fdump-rtl-ce3</code></dt>
<dd><p><samp>-fdump-rtl-ce1</samp>, <samp>-fdump-rtl-ce2</samp>, and
<samp>-fdump-rtl-ce3</samp> enable dumping after the three
if conversion passes.
</p>
<a name="index-fdump_002drtl_002dcprop_005fhardreg"></a>
</dd>
<dt><code>-fdump-rtl-cprop_hardreg</code></dt>
<dd><p>Dump after hard register copy propagation.
</p>
<a name="index-fdump_002drtl_002dcsa"></a>
</dd>
<dt><code>-fdump-rtl-csa</code></dt>
<dd><p>Dump after combining stack adjustments.
</p>
<a name="index-fdump_002drtl_002dcse1"></a>
<a name="index-fdump_002drtl_002dcse2"></a>
</dd>
<dt><code>-fdump-rtl-cse1</code></dt>
<dt><code>-fdump-rtl-cse2</code></dt>
<dd><p><samp>-fdump-rtl-cse1</samp> and <samp>-fdump-rtl-cse2</samp> enable dumping after
the two common subexpression elimination passes.
</p>
<a name="index-fdump_002drtl_002ddce"></a>
</dd>
<dt><code>-fdump-rtl-dce</code></dt>
<dd><p>Dump after the standalone dead code elimination passes.
</p>
<a name="index-fdump_002drtl_002ddbr"></a>
</dd>
<dt><code>-fdump-rtl-dbr</code></dt>
<dd><p>Dump after delayed branch scheduling.
</p>
<a name="index-fdump_002drtl_002ddce1"></a>
<a name="index-fdump_002drtl_002ddce2"></a>
</dd>
<dt><code>-fdump-rtl-dce1</code></dt>
<dt><code>-fdump-rtl-dce2</code></dt>
<dd><p><samp>-fdump-rtl-dce1</samp> and <samp>-fdump-rtl-dce2</samp> enable dumping after
the two dead store elimination passes.
</p>
<a name="index-fdump_002drtl_002deh"></a>
</dd>
<dt><code>-fdump-rtl-eh</code></dt>
<dd><p>Dump after finalization of EH handling code.
</p>
<a name="index-fdump_002drtl_002deh_005franges"></a>
</dd>
<dt><code>-fdump-rtl-eh_ranges</code></dt>
<dd><p>Dump after conversion of EH handling range regions.
</p>
<a name="index-fdump_002drtl_002dexpand"></a>
</dd>
<dt><code>-fdump-rtl-expand</code></dt>
<dd><p>Dump after RTL generation.
</p>
<a name="index-fdump_002drtl_002dfwprop1"></a>
<a name="index-fdump_002drtl_002dfwprop2"></a>
</dd>
<dt><code>-fdump-rtl-fwprop1</code></dt>
<dt><code>-fdump-rtl-fwprop2</code></dt>
<dd><p><samp>-fdump-rtl-fwprop1</samp> and <samp>-fdump-rtl-fwprop2</samp> enable
dumping after the two forward propagation passes.
</p>
<a name="index-fdump_002drtl_002dgcse1"></a>
<a name="index-fdump_002drtl_002dgcse2"></a>
</dd>
<dt><code>-fdump-rtl-gcse1</code></dt>
<dt><code>-fdump-rtl-gcse2</code></dt>
<dd><p><samp>-fdump-rtl-gcse1</samp> and <samp>-fdump-rtl-gcse2</samp> enable dumping
after global common subexpression elimination.
</p>
<a name="index-fdump_002drtl_002dinit_002dregs"></a>
</dd>
<dt><code>-fdump-rtl-init-regs</code></dt>
<dd><p>Dump after the initialization of the registers.
</p>
<a name="index-fdump_002drtl_002dinitvals"></a>
</dd>
<dt><code>-fdump-rtl-initvals</code></dt>
<dd><p>Dump after the computation of the initial value sets.
</p>
<a name="index-fdump_002drtl_002dinto_005fcfglayout"></a>
</dd>
<dt><code>-fdump-rtl-into_cfglayout</code></dt>
<dd><p>Dump after converting to cfglayout mode.
</p>
<a name="index-fdump_002drtl_002dira"></a>
</dd>
<dt><code>-fdump-rtl-ira</code></dt>
<dd><p>Dump after iterated register allocation.
</p>
<a name="index-fdump_002drtl_002djump"></a>
</dd>
<dt><code>-fdump-rtl-jump</code></dt>
<dd><p>Dump after the second jump optimization.
</p>
<a name="index-fdump_002drtl_002dloop2"></a>
</dd>
<dt><code>-fdump-rtl-loop2</code></dt>
<dd><p><samp>-fdump-rtl-loop2</samp> enables dumping after the rtl
loop optimization passes.
</p>
<a name="index-fdump_002drtl_002dmach"></a>
</dd>
<dt><code>-fdump-rtl-mach</code></dt>
<dd><p>Dump after performing the machine dependent reorganization pass, if that
pass exists.
</p>
<a name="index-fdump_002drtl_002dmode_005fsw"></a>
</dd>
<dt><code>-fdump-rtl-mode_sw</code></dt>
<dd><p>Dump after removing redundant mode switches.
</p>
<a name="index-fdump_002drtl_002drnreg"></a>
</dd>
<dt><code>-fdump-rtl-rnreg</code></dt>
<dd><p>Dump after register renumbering.
</p>
<a name="index-fdump_002drtl_002doutof_005fcfglayout"></a>
</dd>
<dt><code>-fdump-rtl-outof_cfglayout</code></dt>
<dd><p>Dump after converting from cfglayout mode.
</p>
<a name="index-fdump_002drtl_002dpeephole2"></a>
</dd>
<dt><code>-fdump-rtl-peephole2</code></dt>
<dd><p>Dump after the peephole pass.
</p>
<a name="index-fdump_002drtl_002dpostreload"></a>
</dd>
<dt><code>-fdump-rtl-postreload</code></dt>
<dd><p>Dump after post-reload optimizations.
</p>
<a name="index-fdump_002drtl_002dpro_005fand_005fepilogue"></a>
</dd>
<dt><code>-fdump-rtl-pro_and_epilogue</code></dt>
<dd><p>Dump after generating the function prologues and epilogues.
</p>
<a name="index-fdump_002drtl_002dsched1"></a>
<a name="index-fdump_002drtl_002dsched2"></a>
</dd>
<dt><code>-fdump-rtl-sched1</code></dt>
<dt><code>-fdump-rtl-sched2</code></dt>
<dd><p><samp>-fdump-rtl-sched1</samp> and <samp>-fdump-rtl-sched2</samp> enable dumping
after the basic block scheduling passes.
</p>
<a name="index-fdump_002drtl_002dree"></a>
</dd>
<dt><code>-fdump-rtl-ree</code></dt>
<dd><p>Dump after sign/zero extension elimination.
</p>
<a name="index-fdump_002drtl_002dseqabstr"></a>
</dd>
<dt><code>-fdump-rtl-seqabstr</code></dt>
<dd><p>Dump after common sequence discovery.
</p>
<a name="index-fdump_002drtl_002dshorten"></a>
</dd>
<dt><code>-fdump-rtl-shorten</code></dt>
<dd><p>Dump after shortening branches.
</p>
<a name="index-fdump_002drtl_002dsibling"></a>
</dd>
<dt><code>-fdump-rtl-sibling</code></dt>
<dd><p>Dump after sibling call optimizations.
</p>
<a name="index-fdump_002drtl_002dsplit1"></a>
<a name="index-fdump_002drtl_002dsplit2"></a>
<a name="index-fdump_002drtl_002dsplit3"></a>
<a name="index-fdump_002drtl_002dsplit4"></a>
<a name="index-fdump_002drtl_002dsplit5"></a>
</dd>
<dt><code>-fdump-rtl-split1</code></dt>
<dt><code>-fdump-rtl-split2</code></dt>
<dt><code>-fdump-rtl-split3</code></dt>
<dt><code>-fdump-rtl-split4</code></dt>
<dt><code>-fdump-rtl-split5</code></dt>
<dd><p>These options enable dumping after five rounds of
instruction splitting.
</p>
<a name="index-fdump_002drtl_002dsms"></a>
</dd>
<dt><code>-fdump-rtl-sms</code></dt>
<dd><p>Dump after modulo scheduling.  This pass is only run on some
architectures.
</p>
<a name="index-fdump_002drtl_002dstack"></a>
</dd>
<dt><code>-fdump-rtl-stack</code></dt>
<dd><p>Dump after conversion from GCC&rsquo;s &ldquo;flat register file&rdquo; registers to the
x87&rsquo;s stack-like registers.  This pass is only run on x86 variants.
</p>
<a name="index-fdump_002drtl_002dsubreg1"></a>
<a name="index-fdump_002drtl_002dsubreg2"></a>
</dd>
<dt><code>-fdump-rtl-subreg1</code></dt>
<dt><code>-fdump-rtl-subreg2</code></dt>
<dd><p><samp>-fdump-rtl-subreg1</samp> and <samp>-fdump-rtl-subreg2</samp> enable dumping after
the two subreg expansion passes.
</p>
<a name="index-fdump_002drtl_002dunshare"></a>
</dd>
<dt><code>-fdump-rtl-unshare</code></dt>
<dd><p>Dump after all rtl has been unshared.
</p>
<a name="index-fdump_002drtl_002dvartrack"></a>
</dd>
<dt><code>-fdump-rtl-vartrack</code></dt>
<dd><p>Dump after variable tracking.
</p>
<a name="index-fdump_002drtl_002dvregs"></a>
</dd>
<dt><code>-fdump-rtl-vregs</code></dt>
<dd><p>Dump after converting virtual registers to hard registers.
</p>
<a name="index-fdump_002drtl_002dweb"></a>
</dd>
<dt><code>-fdump-rtl-web</code></dt>
<dd><p>Dump after live range splitting.
</p>
<a name="index-fdump_002drtl_002dregclass"></a>
<a name="index-fdump_002drtl_002dsubregs_005fof_005fmode_005finit"></a>
<a name="index-fdump_002drtl_002dsubregs_005fof_005fmode_005ffinish"></a>
<a name="index-fdump_002drtl_002ddfinit"></a>
<a name="index-fdump_002drtl_002ddfinish"></a>
</dd>
<dt><code>-fdump-rtl-regclass</code></dt>
<dt><code>-fdump-rtl-subregs_of_mode_init</code></dt>
<dt><code>-fdump-rtl-subregs_of_mode_finish</code></dt>
<dt><code>-fdump-rtl-dfinit</code></dt>
<dt><code>-fdump-rtl-dfinish</code></dt>
<dd><p>These dumps are defined but always produce empty files.
</p>
<a name="index-da"></a>
<a name="index-fdump_002drtl_002dall"></a>
</dd>
<dt><code>-da</code></dt>
<dt><code>-fdump-rtl-all</code></dt>
<dd><p>Produce all the dumps listed above.
</p>
<a name="index-dA"></a>
</dd>
<dt><code>-dA</code></dt>
<dd><p>Annotate the assembler output with miscellaneous debugging information.
</p>
<a name="index-dD-1"></a>
</dd>
<dt><code>-dD</code></dt>
<dd><p>Dump all macro definitions, at the end of preprocessing, in addition to
normal output.
</p>
<a name="index-dH"></a>
</dd>
<dt><code>-dH</code></dt>
<dd><p>Produce a core dump whenever an error occurs.
</p>
<a name="index-dp"></a>
</dd>
<dt><code>-dp</code></dt>
<dd><p>Annotate the assembler output with a comment indicating which
pattern and alternative is used.  The length and cost of each instruction are
also printed.
</p>
<a name="index-dP"></a>
</dd>
<dt><code>-dP</code></dt>
<dd><p>Dump the RTL in the assembler output as a comment before each instruction.
Also turns on <samp>-dp</samp> annotation.
</p>
<a name="index-dx"></a>
</dd>
<dt><code>-dx</code></dt>
<dd><p>Just generate RTL for a function instead of compiling it.  Usually used
with <samp>-fdump-rtl-expand</samp>.
</p></dd>
</dl>

<a name="index-fdump_002ddebug"></a>
</dd>
<dt><code>-fdump-debug</code></dt>
<dd><p>Dump debugging information generated during the debug
generation phase.
</p>
<a name="index-fdump_002dearlydebug"></a>
</dd>
<dt><code>-fdump-earlydebug</code></dt>
<dd><p>Dump debugging information generated during the early debug
generation phase.
</p>
<a name="index-fdump_002dnoaddr"></a>
</dd>
<dt><code>-fdump-noaddr</code></dt>
<dd><p>When doing debugging dumps, suppress address output.  This makes it more
feasible to use diff on debugging dumps for compiler invocations with
different compiler binaries and/or different
text / bss / data / heap / stack / dso start locations.
</p>
<a name="index-freport_002dbug"></a>
</dd>
<dt><code>-freport-bug</code></dt>
<dd><p>Collect and dump debug information into a temporary file if an
internal compiler error (ICE) occurs.
</p>
<a name="index-fdump_002dunnumbered"></a>
</dd>
<dt><code>-fdump-unnumbered</code></dt>
<dd><p>When doing debugging dumps, suppress instruction numbers and address output.
This makes it more feasible to use diff on debugging dumps for compiler
invocations with different options, in particular with and without
<samp>-g</samp>.
</p>
<a name="index-fdump_002dunnumbered_002dlinks"></a>
</dd>
<dt><code>-fdump-unnumbered-links</code></dt>
<dd><p>When doing debugging dumps (see <samp>-d</samp> option above), suppress
instruction numbers for the links to the previous and next instructions
in a sequence.
</p>
<a name="index-fdump_002dipa"></a>
</dd>
<dt><code>-fdump-ipa-<var>switch</var></code></dt>
<dt><code>-fdump-ipa-<var>switch</var>-<var>options</var></code></dt>
<dd><p>Control the dumping at various stages of inter-procedural analysis
language tree to a file.  The file name is generated by appending a
switch specific suffix to the source file name, and the file is created
in the same directory as the output file.  The following dumps are
possible:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Enables all inter-procedural analysis dumps.
</p>
</dd>
<dt>&lsquo;<samp>cgraph</samp>&rsquo;</dt>
<dd><p>Dumps information about call-graph optimization, unused function removal,
and inlining decisions.
</p>
</dd>
<dt>&lsquo;<samp>inline</samp>&rsquo;</dt>
<dd><p>Dump after function inlining.
</p>
</dd>
</dl>

<p>Additionally, the options <samp>-optimized</samp>, <samp>-missed</samp>,
<samp>-note</samp>, and <samp>-all</samp> can be provided, with the same meaning
as for <samp>-fopt-info</samp>, defaulting to <samp>-optimized</samp>.
</p>
<p>For example, <samp>-fdump-ipa-inline-optimized-missed</samp> will emit
information on callsites that were inlined, along with callsites
that were not inlined.
</p>
<p>By default, the dump will contain messages about successful
optimizations (equivalent to <samp>-optimized</samp>) together with
low-level details about the analysis.
</p>
<a name="index-fdump_002dlang"></a>
</dd>
<dt><code>-fdump-lang</code></dt>
<dd><p>Dump language-specific information.  The file name is made by appending
<samp>.lang</samp> to the source file name.
</p>
<a name="index-fdump_002dlang_002dall"></a>
<a name="index-fdump_002dlang-1"></a>
</dd>
<dt><code>-fdump-lang-all</code></dt>
<dt><code>-fdump-lang-<var>switch</var></code></dt>
<dt><code>-fdump-lang-<var>switch</var>-<var>options</var></code></dt>
<dt><code>-fdump-lang-<var>switch</var>-<var>options</var>=<var>filename</var></code></dt>
<dd><p>Control the dumping of language-specific information.  The <var>options</var>
and <var>filename</var> portions behave as described in the
<samp>-fdump-tree</samp> option.  The following <var>switch</var> values are
accepted:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>all</samp>&rsquo;</dt>
<dd>
<p>Enable all language-specific dumps.
</p>
</dd>
<dt>&lsquo;<samp>class</samp>&rsquo;</dt>
<dd><p>Dump class hierarchy information.  Virtual table information is emitted
unless &rsquo;<samp>slim</samp>&rsquo; is specified.  This option is applicable to C++ only.
</p>
</dd>
<dt>&lsquo;<samp>module</samp>&rsquo;</dt>
<dd><p>Dump module information.  Options <samp>lineno</samp> (locations),
<samp>graph</samp> (reachability), <samp>blocks</samp> (clusters),
<samp>uid</samp> (serialization), <samp>alias</samp> (mergeable),
<samp>asmname</samp> (Elrond), <samp>eh</samp> (mapper) &amp; <samp>vops</samp>
(macros) may provide additional information.  This option is
applicable to C++ only.
</p>
</dd>
<dt>&lsquo;<samp>raw</samp>&rsquo;</dt>
<dd><p>Dump the raw internal tree data.  This option is applicable to C++ only.
</p>
</dd>
</dl>

<a name="index-fdump_002dpasses"></a>
</dd>
<dt><code>-fdump-passes</code></dt>
<dd><p>Print on <samp>stderr</samp> the list of optimization passes that are turned
on and off by the current command-line options.
</p>
<a name="index-fdump_002dstatistics"></a>
</dd>
<dt><code>-fdump-statistics-<var>option</var></code></dt>
<dd><p>Enable and control dumping of pass statistics in a separate file.  The
file name is generated by appending a suffix ending in
&lsquo;<samp>.statistics</samp>&rsquo; to the source file name, and the file is created in
the same directory as the output file.  If the &lsquo;<samp>-<var>option</var></samp>&rsquo;
form is used, &lsquo;<samp>-stats</samp>&rsquo; causes counters to be summed over the
whole compilation unit while &lsquo;<samp>-details</samp>&rsquo; dumps every event as
the passes generate them.  The default with no option is to sum
counters for each function compiled.
</p>
<a name="index-fdump_002dtree_002dall"></a>
<a name="index-fdump_002dtree"></a>
</dd>
<dt><code>-fdump-tree-all</code></dt>
<dt><code>-fdump-tree-<var>switch</var></code></dt>
<dt><code>-fdump-tree-<var>switch</var>-<var>options</var></code></dt>
<dt><code>-fdump-tree-<var>switch</var>-<var>options</var>=<var>filename</var></code></dt>
<dd><p>Control the dumping at various stages of processing the intermediate
language tree to a file.  If the &lsquo;<samp>-<var>options</var></samp>&rsquo;
form is used, <var>options</var> is a list of &lsquo;<samp>-</samp>&rsquo; separated options
which control the details of the dump.  Not all options are applicable
to all dumps; those that are not meaningful are ignored.  The
following options are available
</p>
<dl compact="compact">
<dt>&lsquo;<samp>address</samp>&rsquo;</dt>
<dd><p>Print the address of each node.  Usually this is not meaningful as it
changes according to the environment and source file.  Its primary use
is for tying up a dump file with a debug environment.
</p></dd>
<dt>&lsquo;<samp>asmname</samp>&rsquo;</dt>
<dd><p>If <code>DECL_ASSEMBLER_NAME</code> has been set for a given decl, use that
in the dump instead of <code>DECL_NAME</code>.  Its primary use is ease of
use working backward from mangled names in the assembly file.
</p></dd>
<dt>&lsquo;<samp>slim</samp>&rsquo;</dt>
<dd><p>When dumping front-end intermediate representations, inhibit dumping
of members of a scope or body of a function merely because that scope
has been reached.  Only dump such items when they are directly reachable
by some other path.
</p>
<p>When dumping pretty-printed trees, this option inhibits dumping the
bodies of control structures.
</p>
<p>When dumping RTL, print the RTL in slim (condensed) form instead of
the default LISP-like representation.
</p></dd>
<dt>&lsquo;<samp>raw</samp>&rsquo;</dt>
<dd><p>Print a raw representation of the tree.  By default, trees are
pretty-printed into a C-like representation.
</p></dd>
<dt>&lsquo;<samp>details</samp>&rsquo;</dt>
<dd><p>Enable more detailed dumps (not honored by every dump option). Also
include information from the optimization passes.
</p></dd>
<dt>&lsquo;<samp>stats</samp>&rsquo;</dt>
<dd><p>Enable dumping various statistics about the pass (not honored by every dump
option).
</p></dd>
<dt>&lsquo;<samp>blocks</samp>&rsquo;</dt>
<dd><p>Enable showing basic block boundaries (disabled in raw dumps).
</p></dd>
<dt>&lsquo;<samp>graph</samp>&rsquo;</dt>
<dd><p>For each of the other indicated dump files (<samp>-fdump-rtl-<var>pass</var></samp>),
dump a representation of the control flow graph suitable for viewing with
GraphViz to <samp><var>file</var>.<var>passid</var>.<var>pass</var>.dot</samp>.  Each function in
the file is pretty-printed as a subgraph, so that GraphViz can render them
all in a single plot.
</p>
<p>This option currently only works for RTL dumps, and the RTL is always
dumped in slim form.
</p></dd>
<dt>&lsquo;<samp>vops</samp>&rsquo;</dt>
<dd><p>Enable showing virtual operands for every statement.
</p></dd>
<dt>&lsquo;<samp>lineno</samp>&rsquo;</dt>
<dd><p>Enable showing line numbers for statements.
</p></dd>
<dt>&lsquo;<samp>uid</samp>&rsquo;</dt>
<dd><p>Enable showing the unique ID (<code>DECL_UID</code>) for each variable.
</p></dd>
<dt>&lsquo;<samp>verbose</samp>&rsquo;</dt>
<dd><p>Enable showing the tree dump for each statement.
</p></dd>
<dt>&lsquo;<samp>eh</samp>&rsquo;</dt>
<dd><p>Enable showing the EH region number holding each statement.
</p></dd>
<dt>&lsquo;<samp>scev</samp>&rsquo;</dt>
<dd><p>Enable showing scalar evolution analysis details.
</p></dd>
<dt>&lsquo;<samp>optimized</samp>&rsquo;</dt>
<dd><p>Enable showing optimization information (only available in certain
passes).
</p></dd>
<dt>&lsquo;<samp>missed</samp>&rsquo;</dt>
<dd><p>Enable showing missed optimization information (only available in certain
passes).
</p></dd>
<dt>&lsquo;<samp>note</samp>&rsquo;</dt>
<dd><p>Enable other detailed optimization information (only available in
certain passes).
</p></dd>
<dt>&lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Turn on all options, except <samp>raw</samp>, <samp>slim</samp>, <samp>verbose</samp>
and <samp>lineno</samp>.
</p></dd>
<dt>&lsquo;<samp>optall</samp>&rsquo;</dt>
<dd><p>Turn on all optimization options, i.e., <samp>optimized</samp>,
<samp>missed</samp>, and <samp>note</samp>.
</p></dd>
</dl>

<p>To determine what tree dumps are available or find the dump for a pass
of interest follow the steps below.
</p>
<ol>
<li> Invoke GCC with <samp>-fdump-passes</samp> and in the <samp>stderr</samp> output
look for a code that corresponds to the pass you are interested in.
For example, the codes <code>tree-evrp</code>, <code>tree-vrp1</code>, and
<code>tree-vrp2</code> correspond to the three Value Range Propagation passes.
The number at the end distinguishes distinct invocations of the same pass.
</li><li> To enable the creation of the dump file, append the pass code to
the <samp>-fdump-</samp> option prefix and invoke GCC with it.  For example,
to enable the dump from the Early Value Range Propagation pass, invoke
GCC with the <samp>-fdump-tree-evrp</samp> option.  Optionally, you may
specify the name of the dump file.  If you don&rsquo;t specify one, GCC
creates as described below.
</li><li> Find the pass dump in a file whose name is composed of three components
separated by a period: the name of the source file GCC was invoked to
compile, a numeric suffix indicating the pass number followed by the
letter &lsquo;<samp>t</samp>&rsquo; for tree passes (and the letter &lsquo;<samp>r</samp>&rsquo; for RTL passes),
and finally the pass code.  For example, the Early VRP pass dump might
be in a file named <samp>myfile.c.038t.evrp</samp> in the current working
directory.  Note that the numeric codes are not stable and may change
from one version of GCC to another.
</li></ol>

<a name="index-fopt_002dinfo"></a>
</dd>
<dt><code>-fopt-info</code></dt>
<dt><code>-fopt-info-<var>options</var></code></dt>
<dt><code>-fopt-info-<var>options</var>=<var>filename</var></code></dt>
<dd><p>Controls optimization dumps from various optimization passes. If the
&lsquo;<samp>-<var>options</var></samp>&rsquo; form is used, <var>options</var> is a list of
&lsquo;<samp>-</samp>&rsquo; separated option keywords to select the dump details and
optimizations.  
</p>
<p>The <var>options</var> can be divided into three groups:
</p><ol>
<li> options describing what kinds of messages should be emitted,
</li><li> options describing the verbosity of the dump, and
</li><li> options describing which optimizations should be included.
</li></ol>
<p>The options from each group can be freely mixed as they are
non-overlapping. However, in case of any conflicts,
the later options override the earlier options on the command
line. 
</p>
<p>The following options control which kinds of messages should be emitted:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>optimized</samp>&rsquo;</dt>
<dd><p>Print information when an optimization is successfully applied. It is
up to a pass to decide which information is relevant. For example, the
vectorizer passes print the source location of loops which are
successfully vectorized.
</p></dd>
<dt>&lsquo;<samp>missed</samp>&rsquo;</dt>
<dd><p>Print information about missed optimizations. Individual passes
control which information to include in the output. 
</p></dd>
<dt>&lsquo;<samp>note</samp>&rsquo;</dt>
<dd><p>Print verbose information about optimizations, such as certain
transformations, more detailed messages about decisions etc.
</p></dd>
<dt>&lsquo;<samp>all</samp>&rsquo;</dt>
<dd><p>Print detailed optimization information. This includes
&lsquo;<samp>optimized</samp>&rsquo;, &lsquo;<samp>missed</samp>&rsquo;, and &lsquo;<samp>note</samp>&rsquo;.
</p></dd>
</dl>

<p>The following option controls the dump verbosity:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>internals</samp>&rsquo;</dt>
<dd><p>By default, only &ldquo;high-level&rdquo; messages are emitted. This option enables
additional, more detailed, messages, which are likely to only be of interest
to GCC developers.
</p></dd>
</dl>

<p>One or more of the following option keywords can be used to describe a
group of optimizations:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>ipa</samp>&rsquo;</dt>
<dd><p>Enable dumps from all interprocedural optimizations.
</p></dd>
<dt>&lsquo;<samp>loop</samp>&rsquo;</dt>
<dd><p>Enable dumps from all loop optimizations.
</p></dd>
<dt>&lsquo;<samp>inline</samp>&rsquo;</dt>
<dd><p>Enable dumps from all inlining optimizations.
</p></dd>
<dt>&lsquo;<samp>omp</samp>&rsquo;</dt>
<dd><p>Enable dumps from all OMP (Offloading and Multi Processing) optimizations.
</p></dd>
<dt>&lsquo;<samp>vec</samp>&rsquo;</dt>
<dd><p>Enable dumps from all vectorization optimizations.
</p></dd>
<dt>&lsquo;<samp>optall</samp>&rsquo;</dt>
<dd><p>Enable dumps from all optimizations. This is a superset of
the optimization groups listed above.
</p></dd>
</dl>

<p>If <var>options</var> is
omitted, it defaults to &lsquo;<samp>optimized-optall</samp>&rsquo;, which means to dump messages
about successful optimizations from all the passes, omitting messages
that are treated as &ldquo;internals&rdquo;.
</p>
<p>If the <var>filename</var> is provided, then the dumps from all the
applicable optimizations are concatenated into the <var>filename</var>.
Otherwise the dump is output onto <samp>stderr</samp>. Though multiple
<samp>-fopt-info</samp> options are accepted, only one of them can include
a <var>filename</var>. If other filenames are provided then all but the
first such option are ignored.
</p>
<p>Note that the output <var>filename</var> is overwritten
in case of multiple translation units. If a combined output from
multiple translation units is desired, <samp>stderr</samp> should be used
instead.
</p>
<p>In the following example, the optimization info is output to
<samp>stderr</samp>:
</p>
<div class="smallexample">
<pre class="smallexample">gcc -O3 -fopt-info
</pre></div>

<p>This example:
</p><div class="smallexample">
<pre class="smallexample">gcc -O3 -fopt-info-missed=missed.all
</pre></div>

<p>outputs missed optimization report from all the passes into
<samp>missed.all</samp>, and this one:
</p>
<div class="smallexample">
<pre class="smallexample">gcc -O2 -ftree-vectorize -fopt-info-vec-missed
</pre></div>

<p>prints information about missed optimization opportunities from
vectorization passes on <samp>stderr</samp>.  
Note that <samp>-fopt-info-vec-missed</samp> is equivalent to 
<samp>-fopt-info-missed-vec</samp>.  The order of the optimization group
names and message types listed after <samp>-fopt-info</samp> does not matter.
</p>
<p>As another example,
</p><div class="smallexample">
<pre class="smallexample">gcc -O3 -fopt-info-inline-optimized-missed=inline.txt
</pre></div>

<p>outputs information about missed optimizations as well as
optimized locations from all the inlining passes into
<samp>inline.txt</samp>.
</p>
<p>Finally, consider:
</p>
<div class="smallexample">
<pre class="smallexample">gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt
</pre></div>

<p>Here the two output filenames <samp>vec.miss</samp> and <samp>loop.opt</samp> are
in conflict since only one output file is allowed. In this case, only
the first option takes effect and the subsequent options are
ignored. Thus only <samp>vec.miss</samp> is produced which contains
dumps from the vectorizer about missed opportunities.
</p>
<a name="index-fsave_002doptimization_002drecord"></a>
</dd>
<dt><code>-fsave-optimization-record</code></dt>
<dd><p>Write a SRCFILE.opt-record.json.gz file detailing what optimizations
were performed, for those optimizations that support <samp>-fopt-info</samp>.
</p>
<p>This option is experimental and the format of the data within the
compressed JSON file is subject to change.
</p>
<p>It is roughly equivalent to a machine-readable version of
<samp>-fopt-info-all</samp>, as a collection of messages with source file,
line number and column number, with the following additional data for
each message:
</p>
<ul>
<li> the execution count of the code being optimized, along with metadata about
whether this was from actual profile data, or just an estimate, allowing
consumers to prioritize messages by code hotness,

</li><li> the function name of the code being optimized, where applicable,

</li><li> the &ldquo;inlining chain&rdquo; for the code being optimized, so that when
a function is inlined into several different places (which might
themselves be inlined), the reader can distinguish between the copies,

</li><li> objects identifying those parts of the message that refer to expressions,
statements or symbol-table nodes, which of these categories they are, and,
when available, their source code location,

</li><li> the GCC pass that emitted the message, and

</li><li> the location in GCC&rsquo;s own code from which the message was emitted

</li></ul>

<p>Additionally, some messages are logically nested within other
messages, reflecting implementation details of the optimization
passes.
</p>
<a name="index-fsched_002dverbose"></a>
</dd>
<dt><code>-fsched-verbose=<var>n</var></code></dt>
<dd><p>On targets that use instruction scheduling, this option controls the
amount of debugging output the scheduler prints to the dump files.
</p>
<p>For <var>n</var> greater than zero, <samp>-fsched-verbose</samp> outputs the
same information as <samp>-fdump-rtl-sched1</samp> and <samp>-fdump-rtl-sched2</samp>.
For <var>n</var> greater than one, it also output basic block probabilities,
detailed ready list information and unit/insn info.  For <var>n</var> greater
than two, it includes RTL at abort point, control-flow and regions info.
And for <var>n</var> over four, <samp>-fsched-verbose</samp> also includes
dependence info.
</p>


<a name="index-fdisable_002d"></a>
<a name="index-fenable_002d"></a>
</dd>
<dt><code>-fenable-<var>kind</var>-<var>pass</var></code></dt>
<dt><code>-fdisable-<var>kind</var>-<var>pass</var>=<var>range-list</var></code></dt>
<dd>
<p>This is a set of options that are used to explicitly disable/enable
optimization passes.  These options are intended for use for debugging GCC.
Compiler users should use regular options for enabling/disabling
passes instead.
</p>
<dl compact="compact">
<dt><code>-fdisable-ipa-<var>pass</var></code></dt>
<dd><p>Disable IPA pass <var>pass</var>. <var>pass</var> is the pass name.  If the same pass is
statically invoked in the compiler multiple times, the pass name should be
appended with a sequential number starting from 1.
</p>
</dd>
<dt><code>-fdisable-rtl-<var>pass</var></code></dt>
<dt><code>-fdisable-rtl-<var>pass</var>=<var>range-list</var></code></dt>
<dd><p>Disable RTL pass <var>pass</var>.  <var>pass</var> is the pass name.  If the same pass is
statically invoked in the compiler multiple times, the pass name should be
appended with a sequential number starting from 1.  <var>range-list</var> is a 
comma-separated list of function ranges or assembler names.  Each range is a number
pair separated by a colon.  The range is inclusive in both ends.  If the range
is trivial, the number pair can be simplified as a single number.  If the
function&rsquo;s call graph node&rsquo;s <var>uid</var> falls within one of the specified ranges,
the <var>pass</var> is disabled for that function.  The <var>uid</var> is shown in the
function header of a dump file, and the pass names can be dumped by using
option <samp>-fdump-passes</samp>.
</p>
</dd>
<dt><code>-fdisable-tree-<var>pass</var></code></dt>
<dt><code>-fdisable-tree-<var>pass</var>=<var>range-list</var></code></dt>
<dd><p>Disable tree pass <var>pass</var>.  See <samp>-fdisable-rtl</samp> for the description of
option arguments.
</p>
</dd>
<dt><code>-fenable-ipa-<var>pass</var></code></dt>
<dd><p>Enable IPA pass <var>pass</var>.  <var>pass</var> is the pass name.  If the same pass is
statically invoked in the compiler multiple times, the pass name should be
appended with a sequential number starting from 1.
</p>
</dd>
<dt><code>-fenable-rtl-<var>pass</var></code></dt>
<dt><code>-fenable-rtl-<var>pass</var>=<var>range-list</var></code></dt>
<dd><p>Enable RTL pass <var>pass</var>.  See <samp>-fdisable-rtl</samp> for option argument
description and examples.
</p>
</dd>
<dt><code>-fenable-tree-<var>pass</var></code></dt>
<dt><code>-fenable-tree-<var>pass</var>=<var>range-list</var></code></dt>
<dd><p>Enable tree pass <var>pass</var>.  See <samp>-fdisable-rtl</samp> for the description
of option arguments.
</p>
</dd>
</dl>

<p>Here are some examples showing uses of these options.
</p>
<div class="smallexample">
<pre class="smallexample">

# disable ccp1 for all functions
   -fdisable-tree-ccp1
# disable complete unroll for function whose cgraph node uid is 1
   -fenable-tree-cunroll=1
# disable gcse2 for functions at the following ranges [1,1],
# [300,400], and [400,1000]
# disable gcse2 for functions foo and foo2
   -fdisable-rtl-gcse2=foo,foo2
# disable early inlining
   -fdisable-tree-einline
# disable ipa inlining
   -fdisable-ipa-inline
# enable tree full unroll
   -fenable-tree-unroll

</pre></div>

<a name="index-fchecking"></a>
<a name="index-fno_002dchecking"></a>
</dd>
<dt><code>-fchecking</code></dt>
<dt><code>-fchecking=<var>n</var></code></dt>
<dd><p>Enable internal consistency checking.  The default depends on
the compiler configuration.  <samp>-fchecking=2</samp> enables further
internal consistency checking that might affect code generation.
</p>
<a name="index-frandom_002dseed"></a>
</dd>
<dt><code>-frandom-seed=<var>string</var></code></dt>
<dd><p>This option provides a seed that GCC uses in place of
random numbers in generating certain symbol names
that have to be different in every compiled file.  It is also used to
place unique stamps in coverage data files and the object files that
produce them.  You can use the <samp>-frandom-seed</samp> option to produce
reproducibly identical object files.
</p>
<p>The <var>string</var> can either be a number (decimal, octal or hex) or an
arbitrary string (in which case it&rsquo;s converted to a number by
computing CRC32).
</p>
<p>The <var>string</var> should be different for every file you compile.
</p>
<a name="index-save_002dtemps"></a>
</dd>
<dt><code>-save-temps</code></dt>
<dd><p>Store the usual &ldquo;temporary&rdquo; intermediate files permanently; name them
as auxiliary output files, as specified described under
<samp>-dumpbase</samp> and <samp>-dumpdir</samp>.
</p>
<p>When used in combination with the <samp>-x</samp> command-line option,
<samp>-save-temps</samp> is sensible enough to avoid overwriting an
input source file with the same extension as an intermediate file.
The corresponding intermediate file may be obtained by renaming the
source file before using <samp>-save-temps</samp>.
</p>
<a name="index-save_002dtemps_003dcwd"></a>
</dd>
<dt><code>-save-temps=cwd</code></dt>
<dd><p>Equivalent to <samp>-save-temps -dumpdir ./</samp>.
</p>
<a name="index-save_002dtemps_003dobj"></a>
</dd>
<dt><code>-save-temps=obj</code></dt>
<dd><p>Equivalent to <samp>-save-temps -dumpdir <samp>outdir/</samp></samp>, where
<samp>outdir/</samp> is the directory of the output file specified after the
<samp>-o</samp> option, including any directory separators.  If the
<samp>-o</samp> option is not used, the <samp>-save-temps=obj</samp> switch
behaves like <samp>-save-temps=cwd</samp>.
</p>
<a name="index-time"></a>
</dd>
<dt><code>-time<span class="roman">[</span>=<var>file</var><span class="roman">]</span></code></dt>
<dd><p>Report the CPU time taken by each subprocess in the compilation
sequence.  For C source files, this is the compiler proper and assembler
(plus the linker if linking is done).
</p>
<p>Without the specification of an output file, the output looks like this:
</p>
<div class="smallexample">
<pre class="smallexample"># cc1 0.12 0.01
# as 0.00 0.01
</pre></div>

<p>The first number on each line is the &ldquo;user time&rdquo;, that is time spent
executing the program itself.  The second number is &ldquo;system time&rdquo;,
time spent executing operating system routines on behalf of the program.
Both numbers are in seconds.
</p>
<p>With the specification of an output file, the output is appended to the
named file, and it looks like this:
</p>
<div class="smallexample">
<pre class="smallexample">0.12 0.01 cc1 <var>options</var>
0.00 0.01 as <var>options</var>
</pre></div>

<p>The &ldquo;user time&rdquo; and the &ldquo;system time&rdquo; are moved before the program
name, and the options passed to the program are displayed, so that one
can later tell what file was being compiled, and with which options.
</p>
<a name="index-fdump_002dfinal_002dinsns"></a>
</dd>
<dt><code>-fdump-final-insns<span class="roman">[</span>=<var>file</var><span class="roman">]</span></code></dt>
<dd><p>Dump the final internal representation (RTL) to <var>file</var>.  If the
optional argument is omitted (or if <var>file</var> is <code>.</code>), the name
of the dump file is determined by appending <code>.gkd</code> to the
dump base name, see <samp>-dumpbase</samp>.
</p>
<a name="index-fcompare_002ddebug"></a>
<a name="index-fno_002dcompare_002ddebug"></a>
</dd>
<dt><code>-fcompare-debug<span class="roman">[</span>=<var>opts</var><span class="roman">]</span></code></dt>
<dd><p>If no error occurs during compilation, run the compiler a second time,
adding <var>opts</var> and <samp>-fcompare-debug-second</samp> to the arguments
passed to the second compilation.  Dump the final internal
representation in both compilations, and print an error if they differ.
</p>
<p>If the equal sign is omitted, the default <samp>-gtoggle</samp> is used.
</p>
<p>The environment variable <code>GCC_COMPARE_DEBUG</code>, if defined, non-empty
and nonzero, implicitly enables <samp>-fcompare-debug</samp>.  If
<code>GCC_COMPARE_DEBUG</code> is defined to a string starting with a dash,
then it is used for <var>opts</var>, otherwise the default <samp>-gtoggle</samp>
is used.
</p>
<p><samp>-fcompare-debug=</samp>, with the equal sign but without <var>opts</var>,
is equivalent to <samp>-fno-compare-debug</samp>, which disables the dumping
of the final representation and the second compilation, preventing even
<code>GCC_COMPARE_DEBUG</code> from taking effect.
</p>
<p>To verify full coverage during <samp>-fcompare-debug</samp> testing, set
<code>GCC_COMPARE_DEBUG</code> to say <samp>-fcompare-debug-not-overridden</samp>,
which GCC rejects as an invalid option in any actual compilation
(rather than preprocessing, assembly or linking).  To get just a
warning, setting <code>GCC_COMPARE_DEBUG</code> to &lsquo;<samp>-w%n-fcompare-debug
not overridden</samp>&rsquo; will do.
</p>
<a name="index-fcompare_002ddebug_002dsecond"></a>
</dd>
<dt><code>-fcompare-debug-second</code></dt>
<dd><p>This option is implicitly passed to the compiler for the second
compilation requested by <samp>-fcompare-debug</samp>, along with options to
silence warnings, and omitting other options that would cause the compiler
to produce output to files or to standard output as a side effect.  Dump
files and preserved temporary files are renamed so as to contain the
<code>.gk</code> additional extension during the second compilation, to avoid
overwriting those generated by the first.
</p>
<p>When this option is passed to the compiler driver, it causes the
<em>first</em> compilation to be skipped, which makes it useful for little
other than debugging the compiler proper.
</p>
<a name="index-gtoggle"></a>
</dd>
<dt><code>-gtoggle</code></dt>
<dd><p>Turn off generation of debug info, if leaving out this option
generates it, or turn it on at level 2 otherwise.  The position of this
argument in the command line does not matter; it takes effect after all
other options are processed, and it does so only once, no matter how
many times it is given.  This is mainly intended to be used with
<samp>-fcompare-debug</samp>.
</p>
<a name="index-fvar_002dtracking_002dassignments_002dtoggle"></a>
<a name="index-fno_002dvar_002dtracking_002dassignments_002dtoggle"></a>
</dd>
<dt><code>-fvar-tracking-assignments-toggle</code></dt>
<dd><p>Toggle <samp>-fvar-tracking-assignments</samp>, in the same way that
<samp>-gtoggle</samp> toggles <samp>-g</samp>.
</p>
<a name="index-Q"></a>
</dd>
<dt><code>-Q</code></dt>
<dd><p>Makes the compiler print out each function name as it is compiled, and
print some statistics about each pass when it finishes.
</p>
<a name="index-ftime_002dreport"></a>
</dd>
<dt><code>-ftime-report</code></dt>
<dd><p>Makes the compiler print some statistics about the time consumed by each
pass when it finishes.
</p>
<a name="index-ftime_002dreport_002ddetails"></a>
</dd>
<dt><code>-ftime-report-details</code></dt>
<dd><p>Record the time consumed by infrastructure parts separately for each pass.
</p>
<a name="index-fira_002dverbose"></a>
</dd>
<dt><code>-fira-verbose=<var>n</var></code></dt>
<dd><p>Control the verbosity of the dump file for the integrated register allocator.
The default value is 5.  If the value <var>n</var> is greater or equal to 10,
the dump output is sent to stderr using the same format as <var>n</var> minus 10.
</p>
<a name="index-flto_002dreport"></a>
</dd>
<dt><code>-flto-report</code></dt>
<dd><p>Prints a report with internal details on the workings of the link-time
optimizer.  The contents of this report vary from version to version.
It is meant to be useful to GCC developers when processing object
files in LTO mode (via <samp>-flto</samp>).
</p>
<p>Disabled by default.
</p>
<a name="index-flto_002dreport_002dwpa"></a>
</dd>
<dt><code>-flto-report-wpa</code></dt>
<dd><p>Like <samp>-flto-report</samp>, but only print for the WPA phase of link-time
optimization.
</p>
<a name="index-fmem_002dreport"></a>
</dd>
<dt><code>-fmem-report</code></dt>
<dd><p>Makes the compiler print some statistics about permanent memory
allocation when it finishes.
</p>
<a name="index-fmem_002dreport_002dwpa"></a>
</dd>
<dt><code>-fmem-report-wpa</code></dt>
<dd><p>Makes the compiler print some statistics about permanent memory
allocation for the WPA phase only.
</p>
<a name="index-fpre_002dipa_002dmem_002dreport"></a>
<a name="index-fpost_002dipa_002dmem_002dreport"></a>
</dd>
<dt><code>-fpre-ipa-mem-report</code></dt>
<dt><code>-fpost-ipa-mem-report</code></dt>
<dd><p>Makes the compiler print some statistics about permanent memory
allocation before or after interprocedural optimization.
</p>
<a name="index-fmultiflags"></a>
</dd>
<dt><code>-fmultiflags</code></dt>
<dd><p>This option enables multilib-aware <code>TFLAGS</code> to be used to build
target libraries with options different from those the compiler is
configured to use by default, through the use of specs (See <a href="Spec-Files.html#Spec-Files">Spec Files</a>) set up by compiler internals, by the target, or by builders at
configure time.
</p>
<p>Like <code>TFLAGS</code>, this allows the target libraries to be built for
portable baseline environments, while the compiler defaults to more
demanding ones.  That&rsquo;s useful because users can easily override the
defaults the compiler is configured to use to build their own programs,
if the defaults are not ideal for their target environment, whereas
rebuilding the runtime libraries is usually not as easy or desirable.
</p>
<p>Unlike <code>TFLAGS</code>, the use of specs enables different flags to be
selected for different multilibs.  The way to accomplish that is to
build with &lsquo;<samp>make TFLAGS=-fmultiflags</samp>&rsquo;, after configuring
&lsquo;<samp>--with-specs=%{fmultiflags:...}</samp>&rsquo;.
</p>
<p>This option is discarded by the driver once it&rsquo;s done processing driver
self spec.
</p>
<p>It is also useful to check that <code>TFLAGS</code> are being used to build
all target libraries, by configuring a non-bootstrap compiler
&lsquo;<samp>--with-specs='%{!fmultiflags:%emissing TFLAGS}'</samp>&rsquo; and building
the compiler and target libraries.
</p>
<a name="index-fprofile_002dreport"></a>
</dd>
<dt><code>-fprofile-report</code></dt>
<dd><p>Makes the compiler print some statistics about consistency of the
(estimated) profile and effect of individual passes.
</p>
<a name="index-fstack_002dusage"></a>
</dd>
<dt><code>-fstack-usage</code></dt>
<dd><p>Makes the compiler output stack usage information for the program, on a
per-function basis.  The filename for the dump is made by appending
<samp>.su</samp> to the <var>auxname</var>.  <var>auxname</var> is generated from the name of
the output file, if explicitly specified and it is not an executable,
otherwise it is the basename of the source file.  An entry is made up
of three fields:
</p>
<ul>
<li> The name of the function.
</li><li> A number of bytes.
</li><li> One or more qualifiers: <code>static</code>, <code>dynamic</code>, <code>bounded</code>.
</li></ul>

<p>The qualifier <code>static</code> means that the function manipulates the stack
statically: a fixed number of bytes are allocated for the frame on function
entry and released on function exit; no stack adjustments are otherwise made
in the function.  The second field is this fixed number of bytes.
</p>
<p>The qualifier <code>dynamic</code> means that the function manipulates the stack
dynamically: in addition to the static allocation described above, stack
adjustments are made in the body of the function, for example to push/pop
arguments around function calls.  If the qualifier <code>bounded</code> is also
present, the amount of these adjustments is bounded at compile time and
the second field is an upper bound of the total amount of stack used by
the function.  If it is not present, the amount of these adjustments is
not bounded at compile time and the second field only represents the
bounded part.
</p>
<a name="index-fstats"></a>
</dd>
<dt><code>-fstats</code></dt>
<dd><p>Emit statistics about front-end processing at the end of the compilation.
This option is supported only by the C++ front end, and
the information is generally only useful to the G++ development team.
</p>
<a name="index-fdbg_002dcnt_002dlist"></a>
</dd>
<dt><code>-fdbg-cnt-list</code></dt>
<dd><p>Print the name and the counter upper bound for all debug counters.
</p>

<a name="index-fdbg_002dcnt"></a>
</dd>
<dt><code>-fdbg-cnt=<var>counter-value-list</var></code></dt>
<dd><p>Set the internal debug counter lower and upper bound.  <var>counter-value-list</var>
is a comma-separated list of <var>name</var>:<var>lower_bound1</var>-<var>upper_bound1</var>
[:<var>lower_bound2</var>-<var>upper_bound2</var>...] tuples which sets
the name of the counter and list of closed intervals.
The <var>lower_bound</var> is optional and is zero
initialized if not set.
For example, with <samp>-fdbg-cnt=dce:2-4:10-11,tail_call:10</samp>,
<code>dbg_cnt(dce)</code> returns true only for second, third, fourth, tenth and
eleventh invocation.
For <code>dbg_cnt(tail_call)</code> true is returned for first 10 invocations.
</p>
<a name="index-print_002dfile_002dname"></a>
</dd>
<dt><code>-print-file-name=<var>library</var></code></dt>
<dd><p>Print the full absolute name of the library file <var>library</var> that
would be used when linking&mdash;and don&rsquo;t do anything else.  With this
option, GCC does not compile or link anything; it just prints the
file name.
</p>
<a name="index-print_002dmulti_002ddirectory"></a>
</dd>
<dt><code>-print-multi-directory</code></dt>
<dd><p>Print the directory name corresponding to the multilib selected by any
other switches present in the command line.  This directory is supposed
to exist in <code>GCC_EXEC_PREFIX</code>.
</p>
<a name="index-print_002dmulti_002dlib"></a>
</dd>
<dt><code>-print-multi-lib</code></dt>
<dd><p>Print the mapping from multilib directory names to compiler switches
that enable them.  The directory name is separated from the switches by
&lsquo;<samp>;</samp>&rsquo;, and each switch starts with an &lsquo;<samp>@</samp>&rsquo; instead of the
&lsquo;<samp>-</samp>&rsquo;, without spaces between multiple switches.  This is supposed to
ease shell processing.
</p>
<a name="index-print_002dmulti_002dos_002ddirectory"></a>
</dd>
<dt><code>-print-multi-os-directory</code></dt>
<dd><p>Print the path to OS libraries for the selected
multilib, relative to some <samp>lib</samp> subdirectory.  If OS libraries are
present in the <samp>lib</samp> subdirectory and no multilibs are used, this is
usually just <samp>.</samp>, if OS libraries are present in <samp>lib<var>suffix</var></samp>
sibling directories this prints e.g. <samp>../lib64</samp>, <samp>../lib</samp> or
<samp>../lib32</samp>, or if OS libraries are present in <samp>lib/<var>subdir</var></samp>
subdirectories it prints e.g. <samp>amd64</samp>, <samp>sparcv9</samp> or <samp>ev6</samp>.
</p>
<a name="index-print_002dmultiarch"></a>
</dd>
<dt><code>-print-multiarch</code></dt>
<dd><p>Print the path to OS libraries for the selected multiarch,
relative to some <samp>lib</samp> subdirectory.
</p>
<a name="index-print_002dprog_002dname"></a>
</dd>
<dt><code>-print-prog-name=<var>program</var></code></dt>
<dd><p>Like <samp>-print-file-name</samp>, but searches for a program such as <code>cpp</code>.
</p>
<a name="index-print_002dlibgcc_002dfile_002dname"></a>
</dd>
<dt><code>-print-libgcc-file-name</code></dt>
<dd><p>Same as <samp>-print-file-name=libgcc.a</samp>.
</p>
<p>This is useful when you use <samp>-nostdlib</samp> or <samp>-nodefaultlibs</samp>
but you do want to link with <samp>libgcc.a</samp>.  You can do:
</p>
<div class="smallexample">
<pre class="smallexample">gcc -nostdlib <var>files</var>&hellip; `gcc -print-libgcc-file-name`
</pre></div>

<a name="index-print_002dsearch_002ddirs"></a>
</dd>
<dt><code>-print-search-dirs</code></dt>
<dd><p>Print the name of the configured installation directory and a list of
program and library directories <code>gcc</code> searches&mdash;and don&rsquo;t do anything else.
</p>
<p>This is useful when <code>gcc</code> prints the error message
&lsquo;<samp>installation problem, cannot exec cpp0: No such file or directory</samp>&rsquo;.
To resolve this you either need to put <samp>cpp0</samp> and the other compiler
components where <code>gcc</code> expects to find them, or you can set the environment
variable <code>GCC_EXEC_PREFIX</code> to the directory where you installed them.
Don&rsquo;t forget the trailing &lsquo;<samp>/</samp>&rsquo;.
See <a href="Environment-Variables.html#Environment-Variables">Environment Variables</a>.
</p>
<a name="index-print_002dsysroot"></a>
</dd>
<dt><code>-print-sysroot</code></dt>
<dd><p>Print the target sysroot directory that is used during
compilation.  This is the target sysroot specified either at configure
time or using the <samp>--sysroot</samp> option, possibly with an extra
suffix that depends on compilation options.  If no target sysroot is
specified, the option prints nothing.
</p>
<a name="index-print_002dsysroot_002dheaders_002dsuffix"></a>
</dd>
<dt><code>-print-sysroot-headers-suffix</code></dt>
<dd><p>Print the suffix added to the target sysroot when searching for
headers, or give an error if the compiler is not configured with such
a suffix&mdash;and don&rsquo;t do anything else.
</p>
<a name="index-dumpmachine"></a>
</dd>
<dt><code>-dumpmachine</code></dt>
<dd><p>Print the compiler&rsquo;s target machine (for example,
&lsquo;<samp>i686-pc-linux-gnu</samp>&rsquo;)&mdash;and don&rsquo;t do anything else.
</p>
<a name="index-dumpversion"></a>
</dd>
<dt><code>-dumpversion</code></dt>
<dd><p>Print the compiler version (for example, <code>3.0</code>, <code>6.3.0</code> or <code>7</code>)&mdash;and don&rsquo;t do
anything else.  This is the compiler version used in filesystem paths and
specs. Depending on how the compiler has been configured it can be just
a single number (major version), two numbers separated by a dot (major and
minor version) or three numbers separated by dots (major, minor and patchlevel
version).
</p>
<a name="index-dumpfullversion"></a>
</dd>
<dt><code>-dumpfullversion</code></dt>
<dd><p>Print the full compiler version&mdash;and don&rsquo;t do anything else. The output is
always three numbers separated by dots, major, minor and patchlevel version.
</p>
<a name="index-dumpspecs"></a>
</dd>
<dt><code>-dumpspecs</code></dt>
<dd><p>Print the compiler&rsquo;s built-in specs&mdash;and don&rsquo;t do anything else.  (This
is used when GCC itself is being built.)  See <a href="Spec-Files.html#Spec-Files">Spec Files</a>.
</p></dd>
</dl>

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<div class="header">
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